Devin Nunes steps away from probe on Russia meddling

Devin Nunes is pursued by reporters as he leaves Capitol Hill in Washington DC on Thursday [Pablo Martinez Monsivais/AP]

The Republican chairman of the House committee investigating alleged Russian meddling in the 2016 US presidential election has temporarily surrendered his leadership post in the panel's probe, citing ethics complaints.

Representative Devin Nunes of California said the decision was prompted by "entirely false and politically motivated" ethics allegations that he said had been filed against him by "several left-wing activist groups".

Nunes is being investigated by the House ethics committee on whether he improperly disclosed classified information.

"The charges are entirely false and politically motivated and are being leveled just as the American people are beginning to learn the truth about the improper unmasking of the identities of US citizens and other abuses of power," Nunes said in a statement.

He added he will continue fulfilling other duties with the committee and wants to talk to the ethics committee as soon as possible to defend himself.

Nunes' move could be seen as a win for Democrats whose cries for an independent panel to investigate Russia's possible ties with the Donald Trump election campaign have grown.

The full 10-member committee is investigating the allegations against Nunes, a departure from the usual procedure of having a smaller subcommittee handle a probe, an indication of the seriousness of the claims.

Sean Spicer, the White House spokesman, declined to comment, saying House decisions about committee chairmen or their activities are "up to them".

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The top Democrat on the committee, Adam Schiff of California, said he appreciated Nunes' decision to step aside.

"We have a fresh opportunity to move forward in the unified and non-partisan way that an investigation of this seriousness demands," he said.

As the majority party in the House, the Republicans will keep the committee chairmanship. Speaker Paul Ryan said Texas Republican Mike Conaway will take over the House investigation.

He said he supported Nunes' decision. "It is clear that this process would be a distraction for the House Intelligence Committee's investigation into Russian interference in our election."

The intelligence committees in both the House and Senate, as well as the FBI, have been investigating Russia's interference in the 2016 election and possible ties with the Trump campaign.

Last month Trump accused - without providing evidence - former president Barack Obama of illegally wiretapping him, and Trump asked the congressional committees to look into this as part of the investigations.

Days later, Nunes - following a meeting with a "secret source" at the White House grounds - said spy agencies had engaged in incidental collection of Trump associates' communications.

The suggestion was interpreted by the president as support for his claim, even though the FBI, Justice Department, and former Obama administration officials said they were not true.

The statement prompted two private watchdog groups, Democracy 21 and Citizens for Responsibility and Ethics in Washington, to ask the House ethics committee to investigate whether Nunes had disclosed classified information he learned from intelligence reports.